Shock absorber for high speed grounding switches



G. H. TAYLOR Jan. 18, 1966 SHOCK ABSORBER FOR HIGH SPEED GROUNDING SWITCHES Filed March 2, 1964 2 Sheets-Sheet l I'IIIIII INVENTOR.

GEO/P65 14f mxzae G. H. TAYLOR Jan. 18, 1966 SHOCK ABSORBER FOR HIGH SPEED GROUNDING SWITCHES 2 Sheets-Sheet 2 Filed March 2, 1964 I NVENTOR. $60,695 ,4. 740 105 United States Patent H 3,230,335 SHOCK ABSORBER FOR HEGH SPEED GROUNDING SWITCHES George H. Taylor, Greensburg, Pa., assignor to l-T-E Circuit Breaker Company, Philadelphia, Pa., 21 corporation of Pennsylvania Filed Mar. 2, 1964, Ser. No. 348,711 4 Claims. (Cl. 200166) The instant invention relates to electrical distribution systems and more particularly to shock absorbing means for automatic high speed grounding switches which are operated so as to perform a closing operation when the closing time is in the order of /3 of a second or less, with the shock absorbing means being so designed as to prevent the switch blade from rebounding from the closed position to a partially open and then to the final closed position.

Numerous applications in the power distribution field require the use of automatic high speed grounding switches. Such switches are more commonly used to provide reliable and economic protection for large power transformers located at some distance from a circuit breaker. In such applications it has been found that high speed grounding switches provide a more reliable and more economical means for tripping a remote breaker than either carrier or microwave relay. A typical high speed grounding switch is fully set forth in US. Patent 3,089,006, entitled, Automatic High Speed Grounding Switch, filed March 14, 1960, by K. A. Thallner, issued May 7, 1963, and assigned to the assignee of the instant invention.

In such high speed grounding switches the switch blade operation is such that it is brought into engagement with a stationary jaw contact at extremely high velocity and is close after impact with a stationary member at the base of the jaw blade such that the closing means must be maintained in order to hold the switch blade into rigid engagement with the jaw contact and further to overcome any rebounding or oscillatory motion.

It has been found that some of this rebounding of the switch blade which occurs may be reduced somewhat by the use of a shock absorber means. One typical shock absorber means which is comprised of resilient washer members is set forth in the above mentioned US. patent, however, it has been found that shock absorbers of such a design sets up a frequency of oscillation through the blade length which tends to introduce a permanent bend into the blade. The amount of bend becomes progressively worse with each grounding switch closure operation. It has therefore become quite important to provide an antirebound means for such high speed closing switches of the type above mentioned which in addition to preventing rebound also prevents oscillations from being set up which, in turn, act to develop a bend in the switch blade of the high speed grounding switch.

The instant invention provides a novel arrangement which acts to utilize the kinetic energy of the high velocity switch blade in order to provide an antirebounding force against the blade at the moment that is about to rebound in order to prevent such an occurrence.

The instant invention is comprised of an antireboundin-g assembly adapted for mounting immediately adjacent the base of the stationary jaws which receive the switch blade of the high speed grounding switch. The rebound assembly is comprised of a substantially Z-shaped member pivoted about its central axis a first portion of which extends into the direction of travel of the switch blade as it moves into engagement with the stationary jaw contacts.

Just prior to the time that the end of the switch blade,

3,239,335 Patented Jan. 18, 1966 ice which engages the stationary jaw contacts, comes to the base of the jaw contacts it makes engagement with a portion of the antirebound device which is in the path of motion of the switch blade. The switch blade moving at high velocity strikes a portion of the antirebound device extending into the path of movement of the switch blade and imparts motion thereto. The switch blade then continues into a position of deep engagement with the stationary jaw contacts until it reaches a point where it strikes against the base of the jaw contact assembly. With the base portion of the jaw contact structure being relatively stationary, this impact causes the switch blade to rebound and to attempt to move in the reverse direction as a result of this impact.

Simultaneously therewith the remaining portion of the substantially Z-shaped antirebound member rotates at high speed due to the angular motion imparted thereto and comes into engagement and moves into the path of motion of the rebounding switch blade. This remaining portion of the antirebound member makes engagement with the switch blade, causing it to be urged again into deep contact with the stationary jaw structure. Spring means are provided for retaining the Z-shaped antirebound member in this position so as to prevent the switch blade assembly from undergoing any rebounding movement. The antirebound assembly maintains this position until the high speed grounding switch is operated so as to disengage the switch blade from its cooperating stationary jaw contact structure. The opening of the high speed switch moves the blade against the Z-shaped antirebound member causing it to be reset in readiness for another high speed closing operation.

The antirebound assembly is relatively simple in design and may be readily mounted upon existing high speed grounding switch structures without the requirement of any modification thereof. It operates successfully to prevent any rebounding of the high speed switch blade so as to prevent any bending of the switch blade which occurs in high speed switch structures not employing such antirebound devices.

It is therefore one object of the instant invention to provide novel antirebound means for high speed switch structures and the like which is so designed as to prevent a switch blade from rebounding during a high speed closing operation.

Another object of the instant invention is to provide a novel antirebound means for use in high speed structures and the like which is so designed as to utilize the kinetic energy of a rapidly moving switch blade in order to prevent rebounding of the switch blade during a high speed closing operation.

Still another object of the instant invention is to provide novel antirebound means for high speed closing switches and the like wherein a novel rotatable rebound member is provided, which rebound member has a portion thereof positioned in the path of the moving switch blade so as to receive kinetic energy from the switch blade which is then utilized to prevent rebound of the switch blade during the closing operation.

These and other objects of the instant invention will become apparent when reading the accompanying description and drawings in which:

FIGURE 1 shows a side plan view of a portion of a high speed switch blade assembly utilizing the antirebound means of the instant invention.

FIGURE 2 is a top view of the assembly of FIGURE 1.

FIGURE 3 shows a view of the antirebound means of FIGURE 1 in the direction of the arrows A-A shown in FIGURES 1 and 4.

FIGURE 4 shows a side view of an alternative arrangement for that shown in FIGURE 1.

Referring now to the drawings, FIGURE 1 shows a portion of a high speed automatic grounding switch assembly which portion is substantially of the type shown in U.S. Patent 3,089,006 previously mentioned. While only a portion of the high-speed switch assembly is shown in FIGURES 1-4 of the instant application, it is sufficient to understand that the switch assembly 10 is normally comprised of a switch blade 11 and cooperating stationary jaw structure 12 which receives the end 11a of switch blade 11 when the switch is in the engaged position. The switch blade 11, only a portion of which is shown, is operated at relatively high speeds into engagement with the jaw structure 12 by a mechanism of the type shown in FIGURE 2 of the above mentioned US. patent.

The switch assembly 10 is further comprised of a metallic supporting member 13 having suitable apertures 14 to secure member 13 to another member 15 which, in turn, is supported by an insulator 16 of a type well known in the art. Insulator 16 is mounted on any other suitable supporting structure (not shown). One typical supporting structure is designated by the numeral and is shown in FIGURE 1 of the above mentioned U. S. patent. The actual physical attitude of the switch assembly is that shown in FIGURE 1 with the insulator mem ber 16 being substantially vertically mounted and with the support member 13 extending in substantially a horizontal direction, however, vertical mounts are also possible and, in some cases, preferred.

The support member 13 is provided with suitable apertures (not shown) for receiving the fastening members 17 and 18, which can best be seen in FIGURE 2. These fastening members act to rigidly secure the arms 12a and 12b of the stationary jaw contact structure 12. The arms 12a and 12b extend in a common direction generally away from support member 13 and are then bent inwardly and back upon themselves at 12c and 12d respectively, to form the remaining arm portions 12e and 12f respectively, which are designed to receive the end 11a of switch blade 11 therebetween.

The support member 13 is provided with still further suitable apertures for receiving the fastening means 19 and 20. The fastening means 19 and 20 rigidly secure the left-hand ends of back-up spring members 21 and 22 respectively. The free ends of the back-up springs 21 and 22 bear against the outer surfaces of arm portions 12c and 12 and act to urge these arm portions 12c and 12 toward one another to provide rigid engagement between the jaw structure 12 and the switch blade 11 when the switch blade is in engagement with the jaw structure.

The support member 13 is provided with still further suitable apertures (not shown) for receiving the fastening members 23 which act to secure a sleet shield 24 to the support member 13. Sleet shield 24 is a substantially elongated member having sides 24a and 24b depending from top surface 240, which surfaces 24a, 24b and 240 act as a canopy so as to protect the jaw structure from the elements, it being understood that such switches are normally employed in outdoor installations.

As can clearly be seen in FIGURE 1 the jaw structure 12 is actually comprised of first and second pairs 12 and 12' of jaws which act to engage the switch blade 11 therebetween. In cases where only one such jaw structure is required the embodiment of FIGURE 4 may be employed.

The antirebound means is shown best in FIGURES 1, 3 and 4 and is comprised of a shock absorber support member 31 having an aperture 32 for receiving fastening means 33. Fastening means 33 acts to secure the antirebound support member 31 to the support member 13 which, in turn, has a downwardly extending portion 13a which depends from the underside of support member 13 and which is provided with a cylindrically-shaped pening 3b fQI receiving the fastening means 33. The

shock absorber support member 31 has a base portion 31a which lies substantially perpendicular to the wall 31b in which the aperture 32 is provided. The base portion 31a is shaped so as to provide a projection 31b extending from one end of support member 31 and which is provided with an aperture 31c for receiving the cylindrical projecting portion 34a of a spring crank member 34. The spring crank member 34 has a substantially annular central portion 34b from which the cylindrical portion 34a extends and further has an upwardly extending cylindrical projection 34c which is offset from its central axis 35 shown in FIGURE 3. This upwardly extending projection 340 is provided with a surrounding annular groove 34d for seating one end 37a of a spring member 37. The opposite end of spring member 37 is secured within the open eye of a cotter pin 38 which, in turn, is secured at its opposite end within a suitable aperture provided in a projection 39 extending from the vertical wall 31b of the antirebound support member 31.

The actual antirebound member 40 is a substantially Z-shaped member so termed because it has first and second arcuate portions 40a and 40]) extending from the central portion thereof and which are much in the shape of a Z. The central portion of the member 40 is a substantially cylindrical portion 400 having a suitable cylindrical opening 40:! for receiving the cylindrical projection 34a which depends from the member 34. Cylindrical portion 400 is further provided with aperture 402 for receiving a pin 41 which acts to secure Z-shaped member 40 to the spring crank member 34. Both spring crank member 34 and Z-shaped member 40 are rotatable about the aperture 310 on the opposite sides of which the spring crank and the Z-shaped member are mounted.

The operation of the antirebound means is as follows:

FIGURE 3 shows the position of the antirebound device immediately prior to a high speed closing operation. As soon as a high speed closing operation is initiated the switch blade 11 moves in a direction shown by arrow 46 in FIGURE 1. Eventually the switch blade 11 strikes the portion 40b of member 40 at the position and in the direction shown by arrow 47 of FIGURE 3. This causes the substantially Z-shaped member 40 to be rotated counterclockwise at high speed as shown by arrow 48. The restraining force of spring member 37 is much less than the force imparted to member 40 by the switch blade 11 which is moving at substantially high speed so as to fail to impart any significant restraining force against the rotational movement of member 40.

As the member 15 begins to rotate the blade 11 continues moving into the engagement with the jaw structure 12 until it strikes the shock absorber support 31 along its forward edge 31d. Just as the blade 11 begins to rebound from the support 31 the second portion 40a of Z-shaped member 40 rotates around to a position occupying the arm portion 40b shown in FIGURE 3. The edge 40f of this arm portion 40a strikes against the switch blade 11 causing the switch blade to be returned toward the forward edge 31d of base support means 31 bringing the blade 11 to rest against the shock absorber supporting member. In this position the projecting pin 34c rotates around to the dotted line position 340' shown in FIGURE 3. After the grounding switch blade 11 closes, the arm portion 40a (which is now in engagement with the switch blade 11) prevents the member 40 from returning to its normal position until the grounding switch blade is open for its next automatic closing operation. When the blade is opened, spring 37 which had been loaded by the counterclockwise motion of member 40, rotates in the clockwise direction as shown by arrow 49 until it returns to the normal position shown in FIGURE 3 in readiness for a subsequent high speed closing operation.

With the arrangement of the instant invention the grounding switch blade 11 does not rebound, it does not attempt to interrupt the flow of ground current once it has established a permanent ground fall and the maintenance of this contact thereby prolongs the electrical life of the blade and jaw parts due to the fact that it keeps arcing between the blade and jaw contacts 11 and 12 respectively, to a minimum.

The shock absorbing action of the antirebound device also prolongs the mechanical life of the high speed grounding switch blade 11. The rebound and the shock absorbers of other designs sets up a frequency of oscillation throughout the entire blade length which tends to introduce a permanent bend in the blade. The amount of bend becomes progressively worse with each grounding switch closure. High speed grounding switches which employ the antirebound device of the instant invention have been found to prevent such a bend in the blade from being produced.

When the switch blade assembly 10 is reset the antirebound device 30 is automatically reset in the manner as previously described with the resetting operation adding substantially nothing to the grounding switch opening effort.

Although there has been described a preferred embodiment of this novel invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appending claims.

What is claimed is:

1. Shock absorber means for use in interrupter switches and the like having a stationary jaw contact and a cooperating movable blade; said shock absorber means comprising a support means, an anti-rebound member and a spring crank; first means for positioning said support means adjacent said stationary jaw contact; said support means having an aperture; said anti-rebound member having a substantially Z-shaped member having a centrally located cylindrical portion having a cylindrical opening therein; a spring crank having a cylindrical projection extending through said aperture and into said cylindrical opening; second means for securing said cylindrical portion to said cylindrical projection; bias means connected between said spring crank and said support means to position said substantially Z-shaped member in the path of movement of said cooperating movable blade.

2. The shock absorber means of claim 1 in which said substantially Z-shaped member has a first and second arcuate shaped blade oriented relative to one another to produce a substantially Z-shaped blade configuration.

3. The shock absorber means of claim 2 in which said bias means is arranged to position said first arcuate shaped blade in the path of movement of said cooperating movable blade.

4. The shock absorber means of claim 3 in which said bias means is a spring member having a first end secured to said support means and a second end secured to said spring crank.

No references cited.

KATHLEEN H. CLAFFY, Primary Examiner. 

1. SHOCK ABSORBER MEANS FOR USE IN INTERRUPTER SWITCHES ANS THE LIKE HAVING A STATIONARY JAW CONTACT AND A COOPERATING MOVABLE BLADE; SAID SHOCK ABSORBER MEANS COMPRISING A SUPPORT MEANS, AN ANTI-REBOUND MEMBER AND A SPRING CRANK; FIRST MEANS FOR POSITIONING SAID SUPPORT MEANS ADJACENT SAID STATIONARY JAW CONTACT; SAID SUPPORT MEANS HAVING AN APERTURE; SAID ANTI-REBOUND MEMBER HAVING A SUBSTANTIALLY Z-SHAPED MEMBER HAVINGW A CENTRALLY LOCATED CYLINDRICAL PORTION HAVING A CYLINDRI- 